1. Field of the Invention
The present invention relates to a chord-name detection apparatus and a chord-name detection program.
2. Discussion of Background
A chord-name detection apparatus has been developed for detecting a chord name from a musical acoustic signal (audio signal) in which the sounds of a plurality of musical instruments are mixed, such as the audio signals of music compact discs (CDs).
In that apparatus, a bass note is used to determine whether a plurality of chords is used in a bar. More specifically, each bar is divided into a first half and a second half; a bass note is detected in each half; and when different bass notes are detected in the first half and the second half, the chord is also detected in each of the first half and the second half.
In that method, however, when different chords are used but an identical bass note is detected, for example, when the C chord is used in the first half of a bar and the Cm chord is used in the second half, since the bass note is identical, the bar is not divided and the C chord is detected in the whole bar.
In addition, in the above apparatus, the bass note is detected in the entire detection zone. In other words, when the detection zone is a bar, a strong note in the entire bar is detected as the bass note. In jazz music where the bass note changes frequently (the bass note changes in units of quarter notes or the like), however, the bass note cannot be detected correctly with this method.